Transimpedance Amplifier Virtual Ground Shunt for Stable High Power
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Solution Overview
Problem
Class-AB and class-G transimpedance amplifiers in envelope tracking amplification systems face challenges in maintaining stability and linearity as bandwidth and output power increase, leading to reduced efficiency and increased costs.
Innovation Solution
Incorporating a shunt resistive element between the inverting input and a reference potential node, along with a current source or capacitive element, in the amplification circuit to improve stability and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If bandwidth and output power are increased in class-AB and class-G transimpedance amplifiers, then amplification capability is improved, but stability and linearity deteriorate
Solution Approach 1:
The patent introduces a feedback mechanism using a feedback resistor connected between the output and the inverting input of the transimpedance amplifier. This feedback path provides negative feedback that stabilizes the amplifier operation, compensates for gain variations, and maintains linearity even at high output power levels and wide bandwidth conditions, directly resolving the stability deterioration problem
2Power
If bandwidth and output power are increased in class-AB and class-G transimpedance amplifiers, then amplification capability is improved, but linearity deteriorates
Solution Approach 1:
The feedback resistor creates a negative feedback loop that linearizes the amplifier's transfer characteristic. By continuously monitoring the output signal and feeding it back to the inverting input, the system compensates for nonlinear distortions, maintaining accurate signal fidelity even at high power levels and extended bandwidth where linearity would normally deteriorate
3Reliability
If conventional amplification circuits are used without shunt resistive element, then circuit complexity is reduced, but noise increases and efficiency decreases
Solution Approach 1:
The shunt resistive element acts as an intermediary component connected between the inverting input and ground. This resistor provides a defined impedance path that reduces noise by preventing floating potential at the virtual ground node, improves efficiency by optimizing current distribution, and enhances stability without requiring complex circuit modifications beyond this single additional element
Data Source
AI summary
Methods and apparatus for amplifying a signal via an amplification circuit are described. An example amplification circuit generally includes an amplifier including an inverting input configured to receive a signal for wireless transmission. The amplification circuit also includes an impedance coupled between the inverting input and an output of the amplifier. The amplification circuit further includes a resistive element including (i) a first terminal coupled to the inverting input and (ii) a second terminal coupled to a reference potential node for the amplification circuit.